1. Field of the Invention
The present invention relates to the receiving technologies, and it particularly relates to method and apparatus for receiving frequency-multiplexed signals.
2. Description of the Related Art
A plurality of channels in digital television broadcasting or NTSC (National Television Standards Committee) type television broadcasting are frequency-multiplexed. And broadcast waves on a plurality of frequency-multiplexed channels are received by a receiving apparatus. To the broadcast waves, the receiving apparatus carries out a conversion of the radio frequencies to intermediate frequencies and a conversion of the intermediate frequencies to baseband frequencies and at the same time extracts a predetermined channel by the use of a band-pass filter. In addition, the receiving apparatus reproduces a program on the extracted predetermined channel (See Reference (1) in the following Related Art List, for instance).
2. Related Art List
    (1) Japanese Patent Application Laid-Open No. 2001-326863
Under these circumstances, the inventor of the present invention has come to recognize a problem as described below. When a receiving apparatus performs a conversion of radio frequencies of received broadcast waves to intermediate frequencies, it extracts a predetermined channel by a band-pass filter. To demodulate a single channel, there is a need for one converter to perform a conversion processing as described above. Accordingly, a plurality of converters are required if a user wants to view a program on a channel and at the same time record another program on another channel, that is, if a plurality of channels are to be demodulated at the same time. Such a use demands a larger scale of a receiving apparatus. Also, if the video data contained in a program on a channel are coded by MPEG (Moving Picture Expert Group) or the like, there will result a certain amount of delay in the decoding processing. As a consequence, when a channel selection is changed, it may take time before the first of the images is displayed.